how to make facebook application?

[Arun]

i have good knowledge of html, css, and javascript. how can i make facebook application and where can i sell application to earn $500 per month.

[S]

http://developers.facebook.com/ is for Facebook developers, which will help you start making Facebook apps. However, I would suggest you learn at least one server-side scripting language (preferably PHP but you can also choose Microsoft's ASP) and a database language like SQL.

[Rolanda Schwaner]

You should make application using facebook api. You can set the application as per needed

[dannyboy9780]

here is a great place to get information about that developers.facebook.com